The present disclosure relates to semiconducting compositions for making semiconducting layers useful in electronic devices, such as thin film transistors (TFTs). Among other advantages, the semiconducting layers exhibit high field effect mobility and good film-forming properties.
Thin film transistors (TFTs) are critical components in modern-age electronics, including, for example, sensors, image scanners, and electronic display devices. TFT circuits using current mainstream silicon technology are too costly for some applications, particularly for large-area electronic devices such as backplane switching circuits for displays (e.g., active matrix liquid crystal monitors or televisions) where high switching speeds are not essential. The high costs of silicon-based TFT circuits are primarily due to the use of capital-intensive silicon manufacturing facilities as well as complex high-temperature, high-vacuum photolithographic fabrication processes under strictly controlled environments. It is generally desired to make TFTs which have not only much lower manufacturing costs, but also appealing mechanical properties such as being physically compact, lightweight, and flexible.
TFTs are generally composed of, on a substrate, an electrically conductive gate electrode, source and drain electrodes, an electrically insulating gate dielectric layer which separates the gate electrode from the source and drain electrodes, and a semiconducting layer which is in contact with the gate dielectric layer and bridges the source and drain electrodes.
Printed organic thin-film transistors (OTFTs) show promise in applications such as RFID tags and LCD displays. Performance of OTFTs can be measured by mobility. The mobility is measured in units of cm2/V·sec; higher mobility is desired. Semiconducting compositions may generally be divided into two classes: small molecules and polymers. Small molecules show high mobility but poor film-forming properties when solution processed. Polymers have good film-forming properties but generally low mobility.
It would be desirable to develop a semiconducting composition that exhibits high field effect mobility and good film-forming properties.